This project combines neuropsychological, neuroimaging, and eye tracking approaches in order to study the functional interactions of PFC and the hippocampus in supporting richly conditional behavior in humans. The experiments test our hypothesis that the hippocampus is critically involved in relational memory representations whereas PFC is involved in more abstract context-guided associative rules. Neuropsychological studies will provide evidence about the necessity of PFC and MTL regions in relational memory and context-dependent associations, and neuroimaging studies will provide evidence about the nature and timing of functional interactions between these regions. For each study, performance assessments will include not only explicit behavioral judgments but also eye movement-based assessment of memory, pioneered in our laboratory. This approach affords sensitive, implicit nr>easures of the strength of relational and context-dependent representations, based on preferential viewing patterns, as they change dynamically during each trial and across learning and retention. Experiments start with a "base" task in common with all the other empirical projects of the Center, and then graduate to more elaborate variants that systematically manipulate the amount and complexity of relational information or the complexity and abstractness of the context-dependent associative rules to be learned, in order to better determine the dependency of each of these aspects of memory on PFC, hippocampus, and their functional interactions, and further, on the directionality of their interactions.